The purpose of a digit exerciser is to both rehabilitate the injured hand and strengthen the well hand. To accomplish this a device must be able to exercise all planes of movement; flexion, extension, abduction, adduction, plus opponens movement and do so from initially very weak exercises progressing to strong resistance exercises. It is important to be able to isolate each joint of the hand so that the specific muscle fibers that serve the joint can be exercised. The optimum device must also offer numerous options to the user and be able to accommodate all sizes of hands. Ability to exercise both hands simultaneously is advantageous.
Examples of previously known forms of exercisers are disclosed in U.S. Pat. Nos. 3,570,849, 3,606,316, and 4,220,327. These exercises do not provide a variety of reaches which can be gradually increased in tension from very weak to very strong. Nor do they provide for isolation of all the joints in the hand. Nor do these provide for exercise of all the heretofore noted planes of movement.